1. Industrial Field of the Invention
The present invention relates to a radio-control automotive working machine and, more particularly, to a traveling control apparatus of a working machine to perform, by radio control, dangerous work such as mowing lawns on steep golf links and mowing grass on river banks.
More specifically, it relates to a clutch operating apparatus and a traveling brake apparatus in radio-control working vehicles, laser-beam control working vehicles, and various working vehicles and wheeled carriers of other unmanned control types in which a brake is directly controlled by an actuator.
2. Description of the Prior Art
In a conventional automotive working machine of an operator riding type, a traveling brake and a traveling clutch are usually unrelated and individually operated. Moreover, a traveling brake and a traveling clutch are never interlocked in a radio-control automotive working machine of a structure comprising a cutter (blade) which is attached on a lower end of an output shaft of a motor provided on a carriage, a radio transmitter, a radio receiver, and an actuator to operate a traveling transmission and steering wheels in response to signals of the receiver.
Furthermore, in a clutch operating apparatus of the conventional radio-control working machine, an actuator output section and a clutch arm are directly connected. When a traveling clutch of a meshing type is turned on, for example, the crest of a driven clutch collides against the crest of a driving (operating) clutch. Consequently, in order to carry out the clutch functioning operation even in this condition reliably with a certain operating force, springs are generally provided in an operation system. Further, when the clutch is disengaged, there is provided a mechanism to operate it forcibly or through strong springs.
Conventionally, a traveling brake apparatus employed in such a radio-control working vehicle or the like is installed outside of a gear case, e.g., near a wheel, or provided on an outer wall or the like of the gear case, so as to operate a brake shoe directly by an actuator or to operate a brake by hydraulic pressure.
Conventional radio-control automotive working machines involve the following problems.
An operator riding type automotive working machine ridden and operated by a general user and a walking type automotive working machine which travels automatically while it is pressed from behind by a general user who does not ride on it, have a long history, and their operations have been generally known to the public. Since the working machine and the operator always move as one, users in a wide range have accepted steering methods of these working machines. However, a radio-control automotive working machine is extremely unique in that the operation is effected by the tip of a finger in touch with a transmitter at a place remote from the working machine. Further, it is difficult for the operator remote from the working machine to grasp the situation of the working machine, so that he is apt to operate it dangerously.
In addition to this condition, the automotive working machine is very dangerous when no traveling brake is installed in it because even if a traveling clutch is disengaged, it will not stop immediately due to inertia on a slope or a flat ground with a small traveling resistance.
However, even in the case where the radio-control automotive working machine includes a traveling brake, it is necessary to effect disengagement of a traveling clutch and brake operation at once by a transmitter unless the brake is interlocked with the traveling clutch. Therefore, especially for a general user who does not drive and operate such a working machine every day, danger avoiding operation in an emergency is more complicated, thereby reducing the effect produced by installing the brake to half.
With a structure in which the brake functions when the traveling clutch is neutral, it is difficult to move the working machine by a human hand push. In consequence, the force of a motor must be always used for moving the working machine so that the operation will be troublesome.
Concerning a mower used on a golf link whose turning radius is small, installation of a differential gear is essential for preventing the mower from damaging a lawn by a slip of its tire when the mower turns. In the case where a mower includes a differential gear, traveling brakes are generally provided on a plurality of wheels. However, along with the traveling brakes, actuators for functioning them must be also installed, thus increasing the cost.
For the danger avoiding operation by the transmitter, it is an absolute condition to be easy and not induce errors. However, the operation of the conventional radio transmitter is complicated.
The above-described problems are solved by the present invention in which a traveling brake interlocking with a traveling clutch is installed to quicken a stop operation of a working machine, a mechanism for releasing the brake is provided to prevent inconvenience in handling the working machine, the brake is connected to only one of the wheels so as to suppress a cost increase for brake installation to the minimum, and mechanisms and locations of switches of a transmitter are elaborately designed to carry out danger avoidance by transmitter operation more reliably.
In the conventional radio-control mower, excessive force is exerted on an operation system of an actuator output section and a clutch arm, which results in troubles. Such troubles are caused less in operation with a hydraulic mechanism or in a hydraulic-type change gear, but they are disadvantageous in cost, size and weight in comparison with a mechanical type (meshing type) transmission mechanism which the invention intends to provide.
In the case of a meshing-type clutch, e.g., a claw clutch, an operation force substantially in proportion to an amount of a transmission load exerted on the clutch is necessary for disengaging the clutch during power transmission. In order to realize this with an actuator as small as possible, it is not favorable to provide springs and the like in the operation system, and the motive power of the actuator must be utilized directly as an operation force most effectively.
On the other hand, shock absorbing means such as springs are indispensable for the operation system in order to avoid an excessive load when the crests of the clutches collide against each other, as described before.
The present invention intends to solve the above-described drawbacks not only in the clutch operating apparatus of the radio-control working machine but also in an operational structure where motive power of an actuator is transmitted to a clutch arm through mechanical transmission, and a clutch of a meshing type is employed.
In order to decrease the working machine in size, weight and cost, a mechanical brake apparatus is more advantageous as the traveling brake apparatus than a hydraulic operation type. However, since a braking force of a general mechanical brake apparatus is in proportion to an operation force of a brake shoe, a powerful actuator is required for operating the brake shoe in a radio-control working vehicle or the like.
Further, in order to ensure a constant brake performance, various equipments are necessary for maintaining the operation force at a certain level and for protecting the brake from water and dust.